I hate to be that person, but I can't think of a word that would end in akis (ακης) except for male names like giannakis (Γιαννάκης) or adonakis (αδωνακης)
Aki generally means "small" and the gender is neuter, but not all words are allowed to end in aki because they may be feminine or masculine in gender (there are a few exceptions here). Some common endings for masculine and feminine words area itsa, oula/oulis, or akis (not the same as aki).
Geneeally speaking, there is no plural for these endings because in most instances you don't use them in the plural. That said, for food when using aki (ακι), the plural is akia (ακια), because whenever a Greek word ends in iota, you add alpha to the end to make it plural. So the plural of a few words ending in aki:
- dolmadaki (ντολμαδάκι) becomes dolmadakia (ντολμαδάκια)
- Spanakopitaki (σπανακοπιτακι) becomes spanakopitakia (σπανακοπιτακια)
- Pswmaki (ψωμάκι) becomes pswmakia (ψωμάκια)
- Neraki (νεράκι) becomes nerakia (νεράκια)
- Pitaki (πατάκι) becomes pitakia (πιτάκια)
But some words end in oula and since oula is a feminine ending, the plural of oula mus be changes to oules. For example
- Gatoula (γατούλα) becomes gatoules (γατούλες)
- Mikroula (μικρούλα) becomes mikroules (μικρούλες)
But with names it doesn't really work the same way, because you don't usually say them in the plural with these endings.